This application claims benefit of Japanese Application No. 11-141494; filed May 21, 1999; the contents of which are incorporated by this reference.
The present invention relates to a flash light emission apparatus with the use of a flash discharge tube of light bulb shape.
For the flash light emission apparatus, the Japanese Patent Application KOKAI Publication No. 63-58420 discloses an apparatus capable of changing the illuminating angle in response to change in the angle of view of a zoom lens by moving the position of a flash part of the flash discharge tube of light bulb shape backward and forward in a direction of the projection of light. This apparatus has a configuration wherein a U-shaped or spiral flash discharge tube is provided movably forward and backward with respect to a central part of a reflector mirror and the flash discharge tube is arranged to be able to move forward or backward by the use of a reciprocating mechanism, wherein when the flash discharge tube is moved forward, the illuminating angle of light that is projected in a forward direction after the light from the flash light emission apparatus is reflected by the reflector mirror becomes narrow, and when the flash discharge tube is moved backward, the illuminating angle of light becomes wider, and thus the illuminating angle can be changed in response to the change in the angle of view of a zoom lens.
On the other hand, as well known to the those in the art, when a reflector mirror having a cross section defined by a quadric curve, such as an ellipsoid and an parabola, is used, if the center location of the reflector mirror (a focal position) is not adjusted to a center of a light emitting part of the flash discharge tube, the luminous intensity distribution that is obtained with the reflector mirror and the discharge tube will be changed for the worse, disabling the effective use of rays of light from the discharge tube.
Then, to solve the problem, it is possible to align the center location of the light emitting part of the flash discharge tube with the focal position of the reflector mirror by applying such a reciprocating mechanism as disclosed in the above-mentioned Patent Application KOKAI Publication.
By the way, the reflector mirror having a cross section which is defined by an ellipsoid or a quadric curve has another focus at a position in front of the reflector mirror depending on the characteristic of its cross section. Therefore, reflected light reflected by the reflector mirror converges at the front focus and diffuses in an area farther than that position. Therefore, when an object stands farther than the above-mentioned front focal position, this reflected light cannot have an effect as auxiliary light.
Moreover, since the flash discharge tubes are mass production goods, the center location of the light emitting part will scatter with respect to its external shape. Therefore, even if the center location of the light emitting part is adjusted by applying such a reciprocating mechanism as disclosed in the above-mentioned Patent Application KOKAI Publication, the adjustment can have an effect only in a direction of the optical axis and hence the adjustment cannot cope with such dispersion, resulting in inconstant luminous intensity distribution from tube to tube. In order to have a constant luminous intensity distribution without dispersion even when adopting a configuration as is disclosed in this Patent Application KOKAI Publication, it is necessary to use a selected flash discharge tube such that a center of its light emitting part is not out of a geometrical center of its external shape, hence resulting in an extremely large cost for the apparatus.
This invention is devised in consideration of the above-mentioned drawback and it is the object of the present invention to provide the flash light emission apparatus that has a configuration whereby internal reflected light can be used effectively as the auxiliary light.
Moreover, it is the further object of the present invention to provide the flash light emission apparatus which is devised to be free from the influence of the variation of the center locations of the light emitting parts of the flash discharge tubes.
According to a first aspect of the present invention there is provided a flash light emission apparatus comprising:
a flash light emitting tube for emitting light;
a reflecting member for reflecting the light from the flash light emitting tube in a forward direction, the reflecting member being constructed to have a concave mirror; and
a trigger member for triggering the flash light emitting tube to set off emission, the trigger member being constructed with an elastic material having a resilient force that presses itself so as to abut constantly against the surface of the flash light emitting tube.
According to a second aspect of the present invention, there is provided a flash light emission apparatus comprising:
a flash light emitting tube for emitting light;
a reflecting member for reflecting the light from the flash light emitting tube in a forward direction, being constructed to have a concave mirror, on which an insertion hole for the flash light emitting tube to be inserted and protruded forwardly is formed in a central part of a rear end of the reflecting member, on an optical axis of the flash light emission apparatus;
a trigger member for triggering the flash light emitting tube to set off the emission, the trigger member being constructed with an elastic material so as to press itself to the direction to abut constantly against the flash light emitting tube; and
a retention mechanism for retaining the flash light emitting tube in such a condition that its light emitting part locates in a forward position, on the optical axis, so that the relative position of the flash light emitting tube with respect to the reflecting member becomes displaceable both in the direction of the optical axis and at least in one direction in a plane perpendicular to the optical axis and also making it possible for the flash light emitting tube to be displaced at least in the mutually-independent two directions simply by applying the amount of force necessary for the displacement on one portion, wherein
the retention mechanism includes:
a retention member for retaining the flash light emitting tube as an integrated combination, being disposed in the rear of the rear end of the reflecting member, on which support axial parts are provided in a protruding manner; and
a main body member provided with slide slots extending along the direction of the optical axis so that the support axial parts are slidably and swingably fitted therewith.
According to a third aspect of the present invention, there is provided a method for adjusting a flash light emission apparatus including: a flash discharge tube; reflecting means for reflecting the light from the flash discharge tube in a forward direction, being provided in the rear of the flash discharge tube; and a trigger wire for triggering the flash discharge tube to set off the emission, having a resilient force that presses itself to the direction to abut against the surface of the flash discharge tube, the method comprising the steps of:
displacing the relative position of the flash discharge tube with respect to the reflecting means by a predetermined amount repeatedly both in the direction of an optical axis of the flash light emission apparatus and at least in one direction in a plane perpendicular to the optical axis by applying the amount of displacement force only on one portion of a retention mechanism for retaining the flash discharge tube;
setting off the flash discharge tube to emit light by triggering it to start the emission with the trigger wire at each time when displacement of the predetermined amount is executed and then reflecting the light mainly in a direction of the optical axis with the reflecting means;
sensing the light with detecting means at a predetermined position; and
finding a position at which a peak is detected with the detecting means.
According to a fourth aspect of the present invention, there is provided a method for adjusting a flash light emission apparatus including: a flash discharge tube; reflecting means for reflecting the light from the flash discharge tube in a forward direction, being provided in the rear of the flash discharge tube; and a trigger wire for triggering the flash discharge tube to set off the emission, having a resilient force that presses itself to the direction to abut against the surface of the above mentioned flash discharge tube, the method comprising the steps of:
disposing a microscope in front of the flash light emission apparatus and at the center location thereof, on an optical axis of the flash light emission apparatus, and aligning an in-focal point of the microscope with the position of the focal position by design of the reflecting means beforehand; and
aligning the center location of the arc of the flash discharge tube with the focal position of the reflecting means through displacing the relative position of the flash discharge tube with respect to the reflecting means both in the direction of the optical axis of the flash light emission apparatus at least in one direction in a plane perpendicular to the optical axis by applying the amount of displacement force only on one portion of a retention mechanism for retaining the flash discharge tube while observing the center location of the arc of the flash discharge tube with the microscope.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.